Silicone hydrogel contact lenses

ABSTRACT

Silicone hydrogel contact lenses are formed from the reaction product of a polymerizable composition comprising at least one hydrophilic vinyl amide-containing monomer, at least one acrylate-containing siloxane monomer, and at least one hydrophilic vinyl ether-containing monomer. The contact lenses have ophthalmically-acceptable surface wettability and can be manufactured without the use of volatile organic solvents.

This application is a National Stage Application of PCT/US2012/026226,filed Feb. 23, 2012, and which claims the benefit under 35 U.S.C.§119(e) of prior U.S. Provisional Patent Application No. 61/447,216,filed Feb. 28, 2011, which is incorporated in its entirety by referenceherein.

FIELD

The field of the invention relates to silicone hydrogel contact lenses.

BACKGROUND

Contact lenses made from silicone hydrogels are rapidly gainingpopularity over contact lenses made from conventional hydrogel materialsbecause, like conventional hydrogel lenses, they are comfortable towear, but they have the added advantage of having higher oxygenpermeability, which is believed to be healthier for the eye. However,contact lenses made from silicone hydrogels often have physicalproperties that make them more difficult to process duringmanufacturing, and typically the lenses need to be extracted in volatileorganic solvents to achieve acceptable surface wettability and gooddimensional stability. The use of volatile organic solvents inmanufacturing presents safety and environmental concerns and adds coststo the manufacturing process.

New formulations of silicone hydrogel contact lenses that can bemanufactured without the use of volatile organic solvents, and thatresult in dimensionally stable contact lenses havingophthalmically-acceptable surface wettabilities are desired.

Some patent documents describing silicone hydrogel contact lensesinclude U.S. Publ. No. 2007/0296914, U.S. Publ. No. 2007/0066706, U.S.Publ. No. 2007/0231292, U.S. Pat. No. 5,965,631, WO 2011/041523, U.S.Pat. No. 5,358,995, European Publ. No. 1870736A1, U.S. Publ. No.2006/063852, U.S. Publ. No. 2011/0009587, and U.S. Publ. No.2009/0234087.

SUMMARY

We have made improved silicone hydrogel contact lenses havingophthalmically acceptably wettable lens surfaces that can bemanufactured without the use of volatile organic solvents. The presentdisclosure is directed to a silicone hydrogel contact lens comprising apolymeric lens body that is a reaction product of a polymerizablecomposition comprising at least one hydrophilic vinyl amide-containingmonomer, at least one acrylate-containing siloxane monomer, and at leastone vinyl ether-containing monomer.

In one example, the polymerizable composition has a total amount ofhydrophilic vinyl amide-containing monomer of from about 50 mol. % toabout 80 mol. %. In one example, the polymerizable composition has atotal amount of acrylate-containing siloxane monomer of from about 2mol. % to about 15 mol. %. In one example, the polymerizable compositionhas a total amount of vinyl ether-containing monomer of from about 2mol. % to about 20 mol. %. In a further example, the polymerizablecomposition has a molar ratio of total amount of hydrophilic vinylamide-containing monomer to total amount of vinyl ether-containingmonomer of from 2:1 to 30:1, respectively.

In one example, the at least one hydrophilic vinyl amide-containingmonomer is selected from N-vinyl-N-methyl acetamide (VMA), or N-vinylpyrrolidone (NVP), or a combination thereof.

In one example, the at least one vinyl ether-containing monomer isselected from 1,4-butanediol vinyl ether (BVE), or ethylene glycol vinylether (EGVE), or diethylene glycol vinyl ether (DEGVE), or1,4-cyclohexanedimethanol vinyl ether (CHDMVE), or a poly(ethyleneglycol) vinyl ether having from 4 to 10 ethylene glycol units, or apoly(ethylene glycol) vinyl ether having more than 10 ethylene glycolunits, or any combination thereof.

In any of the foregoing examples, the polymerizable composition mayfurther comprise at least one vinyl-containing cross-linking agent. Inone example the at least one vinyl-containing cross-linking agent isselected from divinyl ether, or divinyl sulfone, or triallyl phthalate,or triallyl isocyanurate, or diallyl phthalate, or diethyleneglycoldivinyl ether, or triethyleneglycol divinyl ether, or any combinationthereof.

Another aspect of the present disclosure is a method of manufacturingthe silicone hydrogel contact lens of any one of the foregoing examplescomprising: polymerizing the polymerizable composition to make thepolymeric lens body, and washing the polymeric lens body with a washingliquid to remove unreacted or partially reacted components from thepolymeric lens body.

DETAILED DESCRIPTION

Silicone hydrogel contact lenses are described herein that can bemanufactured without the use of volatile organic solvents. The contactlenses have good manufacturing processability, are dimensionally stable,and have ophthalmically-acceptable surface wettability. The siliconehydrogel contact lens comprises a polymeric lens body that is thereaction product of a polymerizable composition comprising at least onehydrophilic vinyl amide-containing monomer, at least oneacrylate-containing siloxane monomer, and at least one vinyl-ethercontaining monomer. In one example, the polymerizable composition has anamount of the at least one vinyl-ether containing monomer that increaseswettability of the contact lens compared to a contact lens made from aformulation lacking the at least one vinyl-ether containing monomer, butthat is otherwise identical.

The following definitions for the quoted terms provided below areapplicable herein unless context indicates otherwise:

A “monomer” refers to any molecule capable of reacting with othermolecules that are the same or different, to form a polymer orcopolymer. Thus, the term encompasses polymerizable pre-polymers andmacromers, there being no size-constraint of the monomer unlessindicated otherwise.

A “vinyl amide-containing monomer” is any vinyl monomer that contains anN-vinyl polymerizable group, and no other polymerizable group, where Ndesignates nitrogen.

A “vinyl ether-containing monomer is any vinyl monomer that contains anO-vinyl polymerizable group, and no other polymerizable group, where 0designates oxygen.

A monomer is considered “hydrophilic” if at least 50 grams of themonomer are fully soluble in 1 liter of water at 20° C. (i.e., ≧5%soluble in water) as determined visibly using a standard shake flaskmethod.

A “siloxane monomer” contains at least one Si—O group, and is typicallyeither “mono-functional” or “multi-functional”, meaning that it haseither one polymerizable group or two or more polymerizable groups,respectively. A “non-siloxane monomer” is a monomer that does notcontain any Si—O groups. An “acrylate-containing siloxane monomer” is asiloxane monomer that has at least one polymerizable acrylate group(e.g. methyl methacrylate, acrylamide, etc.).

A “polymerizable composition” is a composition comprising polymerizableingredients, where the composition has not yet been subjected toconditions that result in polymerization of the polymerizableingredients.

We have discovered that the inclusion of at least one vinyl-ethercontaining monomer in a polymerizable composition comprising at leastone acrylate-containing siloxane monomer and at least one vinyl-amidemonomer can be polymerized to provide a polymeric lens body that can beprocessed without volatile organic solvents and result in contact lensesthat have ophthalmically-acceptable surface wettability. Referencesherein to ‘at least one’ of a type of ingredient refer to both a) asingle ingredient, and b) a combination of two or more ingredients ofthe same type.

In one example, the polymerizable composition has a total amount ofhydrophilic vinyl amide-containing monomer of from about 50, 55, or 60molar percent (mol. %) up to about 70, 75, 80, or 85 mol. %; a totalamount of vinyl ether-containing monomer of from about 2, 4, or 6 mol. %up to about 10, 15, 20, or 25 mol. %; and a total amount ofacrylate-containing siloxane monomer of from about 2, 3, 4, 5, or 6 mol.% up to about 8, 10, 12, 15, 18, or 20 mol. %, where molar percentvalues are based upon total moles of reactive ingredients in thepolymerizable composition, with non-reactive ingredients, such asdiluents and other non-reactive components, being excluded from thecalculation. References herein to ‘a total amount’ of a particularcomponent (i.e. a combination of two or more ingredients of the sametype) in a polymerizable composition refer to the sum of the amounts ofall ingredients of the same type. Further, throughout this disclosure,when a series of values is presented with a qualifier preceding thefirst value, the qualifier is intended to implicitly precede each valuein the series unless context indicates otherwise. For example, in theabove listing of molar percent ranges for the total amount ofhydrophilic vinyl amide-containing monomer, it is intended that thequalifier “from about” implicitly precedes the values of 50, 55, and 60;and the qualifier “up to about” implicitly precedes the values of 70,75, 80, and 85. Also, throughout this disclosure, when a series ofvalues is presented with a unit of measurement following the last valueof the series, the unit of measurement is intended to implicitly followeach preceding value in the series unless context indicates otherwise.For example, in the above listing of molar percent ranges for the totalamount of hydrophilic vinyl amide-containing monomer, it is intendedthat the unit of measurement “mol. %” implicitly follows the values of50, 55, 70, 75, and 80. Also, when a series of lower limit ranges and aseries of upper limit ranges are provided, all combinations of theprovided ranges are contemplated as if each combination werespecifically listed. For example, in the above listing of molar percentranges for the total amount of hydrophilic vinyl amide-containingmonomer, all 12 possible molar percent ranges are contemplated (i.e.from 50 to 70 mol. %, from 50 to 75 mol. % . . . from 60 to 80 mol. %,and from 60 to 85 mol. %). Also, throughout this disclosure a referenceto “an example” or “a specific example” or similar phrase, is intendedto introduce a feature or features of the contact lens, polymerizablecomposition, or method of manufacture (depending on context) that can becombined with any combination of previously-described orsubsequently-described examples (i.e. features), unless a particularcombination of features is mutually exclusive, or if context indicatesotherwise.

In some examples, the hydrophilic vinyl amide-containing monomer can beselected from N-vinyl-N-methyl acetamide (VMA), or N-vinyl pyrrolidone(NVP), or N-vinyl formamide, or N-vinyl acetamide, or N-vinyl-N-ethylacetamide, or N-vinyl isopropylamide, or N-vinyl caprolactam, orN-vinyl-N-ethyl formamide, or any combination thereof. In some examples,the at least one hydrophilic vinyl amide-containing monomer consists ofVMA or NVP, or a combination of VMA and NVP.

The vinyl ether-containing monomer can be selected from 1,4-butanediolvinyl ether (BVE), or ethylene glycol vinyl ether (EGVE), or diethyleneglycol vinyl ether (DEGVE), or 1,4-cyclohexanedimethanol vinyl ether(CHDMVE), or a poly(ethylene glycol) vinyl ether having from 4 to 10ethylene glycol units, or a poly(ethylene glycol) vinyl ether havingmore than 10 ethylene glycol units, or any combination thereof. In someexamples, the vinyl ether-containing monomer can be a poly(ethyleneglycol) vinyl ether having at least 1, 2, or 3 ethylene glycol units andup to 4, 6, 8, or 10 ethylene glycol units. The polymerizablecomposition can have a molar ratio of the total amount of vinylamide-containing monomer to the total amount of vinyl ether-containingmonomer of from about 2:1, 3:1, 4:1, or 5:1 up to about 15:1, 20:1,25:1, or 30:1 respectively.

One or more vinyl-containing monomers, in addition to the hydrophilicvinyl amide-containing monomers and vinyl ether-containing monomers, maybe included in the polymerizable compositions described herein. As usedherein, a “vinyl-containing monomer” is any non-siloxane monomer thathas a single polymerizable carbon-carbon double bond (i.e., a vinylgroup) present in its molecular structure, where the carbon-carbondouble bond of the vinyl group is less reactive than the carbon-carbondouble bond present in an acrylate or a methacrylate polymerizable groupunder free radical polymerization. Thus, while a carbon-carbon doublebond is present in acrylate groups and methacrylate groups, as usedherein, monomers comprising a single acrylate or methacrylatepolymerizable group are not considered to be vinyl-containing monomers.Thus, for example, vinyl monomers having a single vinyl ester or allylester polymerizable group may be included in the polymerizablecomposition in addition to the vinyl amide-containing monomers and vinylether-containing monomers.

In various examples where more than one hydrophilic vinyl-containingmonomer is included in the polymerizable composition, at least 50%, 60%,70% or 80% by weight of the hydrophilic vinyl-containing monomer has asolubility in water of ≧10%, 15% or 20%. In a specific example, 100% ofthe hydrophilic vinyl-containing monomer in the polymerizablecomposition has a solubility in water of ≧10%, 15%, or 20%. Thehydrophilic vinyl-containing monomer typically has a molecular weight ofabout 75 to about 500, and more typically about 75 to 250.

Acrylate-containing siloxane monomers that can be used in thepolymerizable compositions described herein are well-known in the field,such as those referenced in the patent publications cited in theBackground section above. The acrylate-containing siloxane monomer maybe mono-functional, bi-functional, or comprise a combination of mono-and bi-functional acrylate-containing siloxane monomers. In exampleswhere the acrylate-containing siloxane monomer consists of one or moremono-functional acrylate-containing siloxane monomers (i.e. it does notcontain any multi-functional acrylate-containing siloxane monomers), thepolymerizable composition will typically further comprise anacrylate-containing cross-linking agent, described further below. In aspecific example, the acrylate-containing siloxane monomer has one ormore polymerizable methacrylate groups. Various non-limiting examples ofsuitable acrylate-containing siloxane monomers include3-[tris(trimethylsiloxy)silyl]propyl methacrylate (“TRIS”),3-methacryloxy-2-hydroxypropyloxy)propylbis(trimethylsiloxy)methylsilane(“SiGMA”), methyldi(trimethylsiloxy)sylylpropylglycerolethylmethacrylate (“SiGEMA”), and monomethacryloxypropyl functionalpolydimethylsiloxanes such as MCR-M07 and MCS-M 11, all available fromGelest (Morrisville, Pa., USA).

In one example, the acrylate-containing siloxane monomer may comprise amonomer represented by formula (I),

where m is an integer from 3 to 10, n is an integer from 0 to 10, R¹ isan alkyl group having 1 to 4 carbon atoms, R² is hydrogen or a methylgroup, and R³ is hydrogen or a methyl group. In a further specificexample, the acrylate-containing siloxane monomer is represented byformula I wherein R¹ is a butyl group, R² is hydrogen, R³ is a methylgroup, m is 4, and n is 1. This particular siloxane monomer isdesignated “Si-1” in the Examples section below. Methods of makingsiloxane monomers represented by formula (I) are described in U.S. Publ.no. 20090299022, incorporated herein by reference.

Yet another exemplary acrylate-containing siloxane monomer isrepresented by formula (II),

wherein R₁ is selected from either hydrogen or a methyl group; R₂ isselected from either hydrogen or a C₁₋₄ hydrocarbon group; m representsan integer of from 0 to 10; n represents an integer of from 4 up toabout 15, 25, or 100; a and b represent integers of 1 or more; a+b isequal to 20-500; b/(a+) is equal to 0.01-0.22; and the configuration ofsiloxane units includes a random configuration. In a more specificexample, the acrylate-containing siloxane monomer is represented byformula II wherein R₁ and R₂ are methyl groups, m is 0, n represents aninteger from about 5 to about 10, a represents an integer of from about70 to about 90, and b represent an integer of from 1 to about 10; thissiloxane monomer is designated “Si-2” in the Examples section below andhas a molecular weight of about 8,000 to about 10,000. Methods of makingcompounds of formula II are described in U.S. Publication no.2009/0234089, incorporated herein by reference.

Another exemplary acrylate-containing siloxane monomer is represented byformula (III),

where n is an integer from about 10 to 15. Siloxane monomers of formulaIII and other suitable monomers are described in U.S. Pat. No. 6,867,245and U.S. Pat. No. 6,310,169, both incorporated herein by reference.

Other suitable acrylate-containing siloxane monomers are represented byformula (IV):

wherein R³ is selected from either hydrogen or a methyl group, mrepresents an integer from 0 to 10, and n represents an integer from 1to 500. In a specific example, the acrylate-containing siloxane monomeris a methacryloxypropyl-terminated polydimethylsiloxane represented byformula III where R³ is a methyl group, m is 0, and n is an integer from40 to 60. This monomer is available from Gelest (Morrisville, Pa., USA)and is referred to as “DMS-R18” from the manufacturer and as “Si-3” inthe Examples below. Additional suitable methacryloxypropyl-terminatedpolydimethylsiloxanes include DMS-R22 and DMS-R31, also available fromGelest.

Yet another suitable acrylate-containing siloxane monomer is representedby formula (V),

wherein n is an integer of about 100 to 150, m and p are both integersof about 5 to 10, and h is an integer of about 2 to 8. Methods of makingcompounds of formula V are described in U.S. Pat. No. 6,867,245,incorporated herein by reference. Additional acrylate-containingsiloxane monomers that can be used in the polymerizable compositiondescribed herein are known in the field (see e.g. U.S. Pat. No.7,572,841, U.S. Publ. no. 2006/0063852, and U.S. Pat. No. 5,998,498,each incorporated herein by reference).

In one example, the acrylate-containing siloxane monomer may comprise acombination of a mono-functional acrylate-containing siloxane monomerand a bi-functional acrylate-containing siloxane monomer. In thisexample, the bi-functional acrylate-containing siloxane monomer may bepresent in the polymerizable composition in amounts of from about 0.04,0.06, 0.08, or 0.10 mol. % and up to about 0.20, 0.25, 0.30, or 0.35mol. %; and the mono-functional acrylate-containing siloxane monomer maybe present in amounts of from about 2, 3, 4 or 5 mol. % up to about 8,10, 12, 15, or 18 mol. %. In one such example, the mono-functionalacrylate-containing siloxane monomer has a molecular weight of less than2,000, 1,500, 1,000, or 750, and the bi-functional acrylate-containingsiloxane monomer has a molecular weight of at least 3,000, 3,500, 4,000,4,500, 5,000, 6,000, 7,000, or 8,000. In the case of polyorganosiloxaneprepolymers, such as those represented by formulas III, IV, and V above,and other polydisperse monomers, the term “molecular weight” as usedherein, refers to the absolute number average molecular weight (in unitsof Daltons) of the monomer as determined by ¹H NMR end-group analysis.In a specific example, the mono-functional acrylate-containing siloxanemonomer has a molecular weight of from about 250 to about 1000, and thebi-functional acrylate-containing siloxane monomer has a molecularweight of from about 5,000 to about 16,000. In a further specificexample, the mono-functional acrylate-containing siloxane monomer has amolecular weight of from about 500 to about 1000, and the bi-functionalacrylate-containing siloxane monomer has a molecular weight of fromabout 5,000 to about 12,000.

In the above-described example wherein the acrylate-containing siloxanemonomer comprises a combination of a mono-functional acrylate-containingsiloxane monomer and a bi-functional acrylate-containing siloxanemonomer, the mono-functional acrylate-containing siloxane monomer andbi-functional acrylate-containing siloxane monomer may be present in thepolymerizable composition at a molar ratio of at least 20:1, 30:1, 40:1,50:1, 75:1 or 100:1, and optionally up to about 150:1, 175:1, 200:1,225:1 or 250:1, respectively.

In one example, the polymerizable composition may further comprise anacrylate-containing monomer to further enhance mechanical strengthand/or stiffness of the lens, or confer other desired properties. Asused herein, an “acrylate-containing monomer” is any non-siloxanemonomer that has a single polymerizable acrylate group (e.g. methylmethacrylate, acrylamide, etc.). When present, the total amount ofacrylate-containing monomer in the polymerizable composition typicallycomprises from about 12, 14, 16, or 18 mol. % and up to about 20, 25, or30 mol. %. In a specific example, the acrylate-containing monomer has apolymerizable methacrylate group. Numerous suitable acrylate-containingmonomers are known in the field. Exemplary acrylate-containing monomersinclude methyl methacrylate (MMA), 2-hydroxybutyl methacrylate (HOB),tert butyl methacrylate (tBMA), N,N-dimethylacrylamide (DMA),2-hydroxyethyl methacrylate (HEMA), ethoxyethyl methacrylamide (EOEMA),ethylene glycol methyl ether methacrylate (EGMA), isobornyl methacrylate(IBM), and combinations thereof.

In one example, the polymerizable composition may further comprise across-linking agent. As used herein, a “cross-linking agent” is anycompound having a molecular weight of less than about 2,000 with two ormore polymerizable ethylenically unsaturated groups. Thus, across-linking agent can react with functional groups on two or morepolymer chains so as to bridge one polymer to another. As used herein,“acrylate-containing cross-linking agent” has at least two polymerizableacrylate groups, and no other type of polymerizable group. A“vinyl-containing cross-linking agent” has at least two polymerizablevinyl groups, and no other type of polymerizable group, where thecarbon-carbon double bond of the vinyl groups are less reactive than thecarbon-carbon double bond present in an acrylate or a methacrylatepolymerizable group under free radical polymerization.

Examples of vinyl-containing cross-linking agents that can be used inthe polymerizable compositions disclosed herein include, withoutlimitation, divinyl ethers, or divinyl sulfones, or triallylisocyanurates, and any combination thereof. Exemplary divinyl ethersinclude diethyleneglycol divinyl ether, or triethyleneglycol divinyl, or1,4-butanediol divinyl ether, or 1,4-cyclohexanedimethanol divinylether, or any combination thereof. Other cross-linking agents suitablefor use in silicone hydrogel polymerizable compositions are known in thefield (see e.g. the patent publications listed in the Backgroundsection). Typically, the vinyl-containing cross-linking agent can havetwo or three polymerizable vinyl groups. The vinyl-containingcross-linking agents, as well as the acrylate-containing cross-linkingagents described further below, typically can have a molecular weight ofless than 1500, 1000, 500, or 250. When present, the total amount ofvinyl-containing cross-linking agent in the polymerizable composition istypically from about 0.02, 0.04, or 0.06 mol. % up to about 0.10, 0.15,or 0.20 mol. %.

Examples of acrylate-containing cross-linking agents that can be used inthe polymerizable compositions disclosed herein, include, withoutlimitation, lower alkylene glycol di(meth)acrylate, poly(loweralkylene)glycol di(meth)acrylate, lower alkylene di(meth)acrylate,trimethylolpropane tri(meth)acrylate, pentaerythritoltetra(meth)acrylate, bisphenol A di(meth)acrylate,methylenebis(meth)acrylamide, and1,3-Bis(3-methacryloxypropyl)tetramethyldisiloxane. In certain examplesthe acrylate-containing cross-linking agent is free of siloxanemoieties, i.e. it is a non-siloxane cross-linking agent. When present,the total amount of acrylate-containing cross-linking agent in thepolymerizable composition is typically from about 0.20, 0.25, 0.30, or0.35 mol. % up to about 0.50, 0.60, 0.70, 0.80, or 1.0 mol. %.

The polymerizable compositions can also be described in terms of thepercentage by weight (wt. %) of each reactive component in thepolymerizable composition, and wt. % ratios of various reactivecomponents, wherein the weight percentages are based on total weight ofreactive components of the composition relative to the total weight ofall reactive components. For example, the polymerizable composition mayhave a total amount of hydrophilic vinyl amide-containing monomer offrom about 20, 25, or 30 wt. % up to about 50, 55, or 60 wt. %; a totalamount of vinyl ether-containing monomer of from about 1, 2, or 4 wt. %up to about 10, 15, or 20 wt. %; and a total amount ofacrylate-containing siloxane monomer of from about 20, 25, or 30 wt. %up to about 50, 55 or 60 wt. %. In one example, the polymerizablecomposition may have a total amount of vinyl-containing cross-linkingagent of from about 0.02, or 0.05 wt. % up to about 0.5, or 1.0 wt. %.In another example, the polymerizable composition has a total amount ofan acrylate-containing cross-linking agent of from about 0.05 wt. % toabout 4 wt. %. In one example, the polymerizable composition may furthercomprise from about 5, or 10 wt. % up to about 20, or 25 wt. % of anacrylate-containing monomer. These wt. % examples of the polymerizablecomposition may be combined with any of the above-described molar ratioand/or molar percentage examples.

Polymerizable compositions described herein result in contact lensesthat have ophthalmically acceptably wettable lens surfaces without theinclusion of a high molecular weight hydrophilic polymer (i.e. apreformed polymer) in the polymerizable composition. In a particularexample, the polymerizable composition is substantially free of ahydrophilic polymer. As used herein, “substantially free” means none oran inconsequential amount, i.e. an amount that has no measurable affecton the physical properties of the lens. However, such hydrophilicpolymers may be included in the polymerizable composition, if desired.Examples of such hydrophilic polymers include polyamides, polylactams(especially polyvinylpyrrolidone), polyimides, polylactones, andpolydextrans, having molecular weights of at least 50,000, and aredescribed in U.S. Pat. No. 6,367,929, incorporated herein by reference.Accordingly, in another example the polymerizable compositionadditionally comprises a hydrophilic polymer in an amount that increasesthe wettability of the contact lens relative to a contact lens thatlacks the hydrophilic polymer but is otherwise identical.

As will be appreciated by those skilled in the art, the polymerizablecomposition will typically comprise non-polymerizable ingredients, inaddition to the polymerizable ingredients, that are conventionally usedin contact lens formulations. For example, the polymerizable compositionwill typically include a polymerization initiator, a UV absorbing agent,and a tinting agent. Additional ingredients may also be included such asan organic diluent, an oxygen scavenger, or a chain transfer agent.Non-limiting examples of these and additional ingredients that may beincluded in the polymerizable composition are provided in U.S.Publication no. 2007/0296914, and below.

Contact lenses can be made from the polymerizable compositions describedherein using curing and other processing methods known in the field,such as cast molding, spin casting, injection molding, forming apolymerized rod that is subsequently lathed, etc. In a specific example,the polymerizable composition is cast molded between molds formed of athermoplastic polymer. The thermoplastic polymer is typically anon-polar material, such as polypropylene, but polar mold materials arealso used in the field. Briefly, a first mold member defining the frontsurface of the contact lens, referred to as a “female mold member”, isfilled with an amount of the polymerizable composition sufficient toform a single polymeric lens body. A second mold member defining theback (i.e. eye-contacting) surface of the contact lens, referred to asthe “male mold member”, is coupled to the female mold member to form amold assembly having a lens-shaped cavity with the amount ofpolymerizable composition therebetween.

The polymerizable composition within the contact lens mold assembly ispolymerized using any suitable curing method. Typically, thepolymerizable composition is exposed to polymerizing amounts of heat orultraviolet light (UV). In the case of UV-curing, also referred to asphotopolymerization, the polymerizable composition typically comprises aphotoinitiator such as benzoin methyl ether, 1-hydroxycyclohexylphenylketone, Darocur or Irgacur (available from Ciba Specialty Chemicals).Photopolymerization methods for contact lenses are described in U.S.Pat. No. 5,760,100. In the case of heat-curing, also referred to asthermal curing, the polymerizable composition typically comprises athermal initiator. Exemplary thermal initiators include2,2′-azobis(2,4-dimethylpentanenitrile) (VAZO-52),2,2′-Azobis(2-methylpropanenitrile) (VAZO-64), and 1,1′-azobis(cyanocyclohexane) (VAZO-88). In an exemplary thermal curing methodthat can be used to polymerize polymerizable compositions describedherein, the mold assemblies are subjected to a first curing temperatureof from about 50 to 65° C., which is maintained for about 15 to 45minutes, and then the temperature is increased to a second temperatureof at least about 70° C. In one such example, the second curingtemperature can be from about 70 to 85° C. and can be maintained forabout 15 to 45 minutes, then the temperature can be increased again toat least about 90° C., and can be maintained until polymerization issubstantially complete, typically at least about 15 minutes. Additionalthermal polymerization methods for contact lenses are described in USPubl. no. 2007/0296914 and U.S. Pat. No. 7,854,866, incorporated hereinby reference.

At the completion of curing, the polymerized material between the moldmembers of the mold assembly has the shape of a contact lens, and isreferred to herein as a “polymeric lens body”. The male and female moldmembers are demolded, i.e. separated, and the polymeric lens body isremoved, i.e. delensed, from the mold member to which it is adhered.These processes are referred to as demolding and delensing,respectively, and a variety of such methods are known to those ofordinary skill in the field. In some methods, the demolding anddelensing processes can comprise a single process step, such as when themolds are separated using a liquid which also removes the polymeric lensbody from the mold. In other methods, such as when a dry-demoldingprocess is used, the polymeric lens body typically remains on one of themold members and is delensed in a subsequent process step. Delensing canalso be a wet or dry process. In one example, delensing is carried outby a “float off” method in which the mold member to which a polymericlens body is adhered is immersed in water. The water may optionally beheated (e.g. up to about 100° C.). Typically, the polymeric lens bodiesfloat off of the mold members in about ten minutes. Dry delensing can becarried out manually, for example using tweezers to remove the polymericlens bodies from the mold member, or they can be removed using anautomated mechanical process, such as described in U.S. Pat. No.7,811,483. Additional demolding and delensing methods for siliconehydrogel contact lenses are described in US Publ No. 2007/0035049.

After delensing, the polymeric lens body is washed to remove unreactedor partially reacted ingredients from the polymeric lens body and tohydrate the polymeric lens body. In a specific example, the polymericlens body is washed in a washing liquid free of volatile organicsolvents (e.g. methanol, ethanol, chloroform, etc.), and all liquidsused to wash the polymeric lens body are free of volatile organicsolvents. This type of washing may also be referred to herein as“organic solvent-free extraction” where “organic solvent” refers tovolatile organic solvents. For example, a washing step that uses aqueoussolutions of surfactants such as Tween 80, without any volatile organicsolvents, is considered to be a volatile organic solvent-freeextraction. In a further example, the polymeric lens body is notcontacted by any volatile organic solvents during the manufacturingprocess (i.e. from the time curing of the polymeric lens body iscomplete until the time it is sealed in its final packaging). While thepolymerizable compositions described herein can be used to makepolymeric lenses bodies that can be washed without the use of volatileorganic solvents, if desired, they can also be washed with organicsolvents. Thus, washing steps can include contacting the polymeric lensbody with a volatile organic solvent, such as a lower alcohol (e.g.methanol, ethanol, etc.), contacting the polymeric lens body withaqueous liquids that may or may not contain a volatile organic solvents,solutes, or combinations thereof. Exemplary washing methods aredescribed in US Pat Publ no. 2007/0296914 and in Example 1 below.

The good wettability of the contact lenses achieved from thepolymerizable compositions described herein avoids the need forpost-polymerization surface modification of the polymeric lens body toimpart wettability. One example of a post-polymerization surfacemodification used to impart wettability is surface plasma treatment (seee.g.U.S. Pat. No. 4,143,949). Another example of a post-polymerizationmodification to impart wettability is the coating of hydrophilicpolymers onto the surface of the polymeric lens body such as by alayer-by-layer technique (see e.g. U.S. Pat. No. 7,582,327), or by theaddition of a hydrophilic polymer into the packaging solution (see e.g.U.S. Pat. No. 7,841,716). Accordingly, in a specific example, the methodof making the contact lens is free of a post-polymerization surfacemodification. For example, the method may not include a plasma surfacemodification of the polymeric lens body and/or a hydrophilic polymer maynot be coated onto the polymeric lens body and/or a hydrophilic polymermay not be added to the packaging solution that is placed into thecontact lens package.

After washing, and any optional surface modifications, the hydratedpolymeric lens body is typically placed into a blister package, glassvial, or other appropriate container, all referred to herein as“packages.” A packaging solution is also added to the container, whichis typically a buffered saline solution such as phosphate- orborate-buffered saline. The packaging solution may optionally containadditional ingredients such as a comfort agent, a hydrophilic polymer, asurfactant or other additive that prevents the polymeric lens body fromsticking to the container, etc. The package is sealed, and the sealedpolymeric lens body is sterilized by sterilizing amounts of radiation,including heat or steam, such as by autoclaving, gamma radiation, e-beamradiation, ultraviolet radiation, etc. The final product is a sterile,packaged ophthalmically-acceptable contact lens.

Typically, lenses that have been processed using organic solvent-freeextraction will have a “wet extractable component”. In specificexamples, the wet extractable component of the final contact lensproduct constitutes about 2 to about 8% of the dry weight of the contactlens, and usually about 3 to about 6% of the dry weight of the contactlens. The percentage of the wet extractable component in a contact lensis determined using a Sohxlet extraction process as follows: Fivefully-hydrated, sterilized contact lenses from a single lot are removedfrom their packages and excess packaging solution is removed from thelenses with a paper towel. The lenses are dried overnight in an 80° C.vacuum oven, then each dried lens is weighed to get the dry weight ofthe lens (W1). Each lens is then placed in a perforated, stackableTeflon thimble, and the thimbles are stacked to form an extractioncolumn with an empty thimble placed at the top of the column. Theextraction column is placed into a small Sohxlet extractor (VWR80068-164) and the extractor is attached to a condenser (VWR 80068-1580)and a 125 ml round bottom flask (VWR-80068-704) containing about 70-80ml methanol. Water is circulated around the condenser and the methanolis heated until it gently bubbles. The lenses are extracted for 4 hoursfrom the time condensed methanol first begins to drop. Themethanol-extracted lenses are removed from the thimbles and driedovernight at 80° C. in a vacuum oven. Each lens is weighed to obtain thedry weight of the extracted lens (W2), and the following calculation ismade for each lens: [(W1−W2)/W1]*100. The average of the five values istaken to be the percentage of wet extractable for each lens of the lotof lenses tested.

The contact lenses described herein are “ophthalmically-acceptable”meaning that the lenses have ophthalmically acceptably wettable lenssurfaces and ionoflux values such that the lenses typically do not causeor are not associated with significant corneal swelling, cornealdehydration (“dry eye”), superior epithelial arcuate lesions (“SEALs”),or other significant discomfort. Determining whether a contact lens isophthalmically acceptable can be achieved using conventional clinicalmethods, such as those performed by an eye care practitioner, and asunderstood by persons of ordinary skill in the art.

In any of the above-described examples, the contact lens may becharacterized by one or more of the following properties: ionoflux,contact angle, oxygen permeability, tensile modulus, equilibrium watercontent, and % energy loss, as detailed in the following sevenparagraphs.

In any of the above-described examples, the contact lens may have anionoflux of less than about 10×10⁻³ mm²/min, 9×10⁻³ mm²/min, 8×10⁻³mm²/min, 7×10⁻³ mm²/min, 6×10⁻³ mm²/min, 5×10⁻³ mm²/min, or 4×10⁻³mm²/min as measured using the “Ionoflux Technique” described in U.S.Pat. No. 5,849,811, incorporated by reference herein, or an equivalentmethod such as the following method that was used to determine theionoflux values provided in the Examples below. A hydrated lens isplaced in 40 ml deionized water for 10 minutes. The lens is then placedin a lens-retaining device, between male and female portions. The maleand female portions include flexible sealing rings which are positionedbetween the lens and the respective male or female portion. Thelens-retaining device is then placed in a threaded lid. The lid isscrewed onto a glass tube to define a donor chamber. The donor chamberis filled with 16 ml of 0.1 molar NaCl solution. A 100 ml beaker, usedas a receiving chamber, is filled with 80 ml of deionized water. Leadsof a conductivity meter and a stir bar are immersed in the deionizedwater of the receiving chamber. The receiving chamber is placed in a 250ml beaker jacket that was filled with about 50 ml deionized water andconnected to a water bath with temperature control set to achieve atemperature of about 35° C. in the receiving chamber. Finally, the donorchamber is immersed in the receiving chamber so that the NaCl solutioninside the donor chamber is level with the water inside the receivingchamber. Once the temperature inside the receiving chamber reaches 35°C., conductivity is recorded for 10 minutes. The conductivity versustime data in each of the examples below was substantially linear.

In any of the above-described examples, the contact lens may have acontact angle of less than about 80°, 70°, or 60°, where the contactangle is the dynamic advancing contact angle as determined using acaptive bubble method using a DSA 100 Drop Shape Analysis System fromKrüss as described in Maldonado-Codina, C. and Morgan, P. B. (2007), Invitro water wettability of silicone hydrogel contact lenses determinedusing the sessile drop and captive bubble techniques. Journal ofBiomedical Materials Research Part A, 83A: 496-502.

In any of the above-described examples, the oxygen permeability of thecontact lens (Dk) may be at least 55 barrers, or at least 60 barrers. Dkvalues can be determined using standard methods in the industry, such asby using an Ox-Tran model oxygen transmission rate test system availablefrom Mocon, Inc (Minneapolis, Minn.). The Dk values provided in theExamples below were determined using the method described by Chhabra etal. (2007), A single-lens polarographic measurement of oxygenpermeability (Dk) for hypertransmissible soft contact lenses.Biomaterials 28: 4331-4342.

In any of the above described examples, the contact lens may have atensile modulus (i.e. Young's modulus) of about 0.2 MPa, 0.3 MPa, or 0.4MPa, up to about 0.7 MPa, 0.8 MPa, or 0.9 MPa as measured by an ANSIZ80.20 standard using an Instron Model 3342 or Model 3343 mechanicaltesting system, or equivalent method. The modulus, elongation, andtensile strength values reported herein were determined using an InstronModel 3342 or 3343 mechanical testing system (Instron Corporation,Norwood, Mass., USA) and Bluehill Materials Testing Software, using acustom built rectangular contact lens cutting die with 4 mm spacing toprepare the rectangular sample strip. The modulus was determined insidea chamber having a relative humidity of least 70%. A lens was soaked inphosphate buffered solution (PBS) for at least 10 minutes prior totesting. While holding the lens concave side up, a central strip of thelens was cut using the cutting die. The thickness of the strip wasdetermined using a calibrated gauge (Rehder electronic thickness gauge,Rehder Development Company, Castro Valley, Calif., USA). Using tweezers,the strip was loaded into the grips of the calibrated Instron apparatus,with the strip fitting over at least 75% of the grip surface of eachgrip. A test method designed to determine the maximum load (N), thetensile strength (MPa), the strain at maximum load (% elongation) andthe mean and standard deviation of the tensile modulus (MPa) was run,and the results were recorded.

In any of the above-described examples, the contact lens may have anequilibrium water content (EWC) of greater than about 30 wt. %, 40 wt. %or 50 wt. % and up to about 60 wt. % or 70 wt. %. To measure EWC, excesssurface water is wiped off of the lens and the lens is weighed to obtainthe hydrated weight. The lens is dried in an oven at 80° C. under avacuum, and weighed. The weight difference is determined by subtractingthe weight of the dry lens from the weight of the hydrated lens. The wt.% EWC of the lens is =(weight difference/hydrated weight)×100. In aspecific example, the contact angle is ≦70° and the equilibrium watercontent is at least about 40 wt. %.

The contact lenses described herein are considered “dimensionallystable” if they are from a batch (i.e. lot) of contact lenses thatexhibit an average dimensional stability variance of ≦±3.0% (i.e. lessthan or equal to plus or minus three percent) as determined by thefollowing method. The chord diameters of twenty lenses from a single lotare measured, and the average “original” diameter is obtained.Concurrently, twenty unopened packages of lenses from the same lot areplaced in an incubator set at 55° C. The lenses are kept at thiselevated temperature storage condition for three months to approximate atwo-year shelf life at 25° C. At the end of three months the packagedlenses are brought to room temperature, removed from their packaging,and measured to obtain the average “final” diameter. The dimensionalstability variance is calculated by the equation:(Diameter_(Final)−Diameter_(Original)/Diameter_(Original))×100. In someexamples, the dimensional stability variance is ≦±2.5% or ≦±2.0%. Inother examples, the lenses have a dimensional stability variance of≦±3.0% as determined using the above-described method except that theincubator is set at 65° C. This elevated temperature storage conditionis considered to approximate a four-year shelf life at 25° C.

In any of the above described examples, the contact lens may have apercent energy loss of at least about 25, 27, or 30 up to about 37, 40,or 45 as determined using a test method in accordance with ANSI Z80.20.The energy loss values reported herein were determined using an InstronModel 3343 (Instron Corporation, Norwood, Mass., USA) mechanical testingsystem, with a 10N force transducer (Instron model no. 2519-101) andBluehill Materials Testing Software including a TestProfiler module.Briefly, the energy loss was determined inside a chamber having arelative humidity of least 70%. A lens was soaked in phosphate bufferedsolution (PBS) for at least 10 minutes prior to testing. Using tweezers,the lens was loaded into the grips of the calibrated Instron apparatus,with the lens loaded vertically between the grips as symmetrically aspossible and fitting over at least 75% of the grip surface of each grip.A test designed to determine the energy required to stretch the lens to100% strain and then return it to 0% strain at a rate of 50 mm/minutewas then run on the lens. The test was conducted only once on a singlelens. Once the test was finished energy loss was calculated: Lost Energy(%)=(Energy to 100% strain−Energy to return to 0% strain)/Energy to 100%strain×100%.

As is evident from the disclosure of the application as a whole,including the claim structure and the specific examples, the exemplarycomponents of the polymerizable composition disclosed herein aretypically combined in embodiments of the invention. For example, theperson skilled in the art would recognise that the polymerizablecomposition of the invention advantageously includes the exemplaryacrylate-containing siloxane monomers disclosed herein in combinationwith the exemplary vinyl ether-containing monomers disclosed hereinand/or in combination with the exemplary hydrophilic vinyl-amidecontaining monomers disclosed herein.

Thus, the acrylate-containing siloxane monomers disclosed in paragraphs[026]-[031] above are, advantageously, present in the polymerizablecompositions of the invention in combination with any of the vinylether-containing monomers disclosed in paragraph [023]. For example,TRIS, SiGMA, SiGEMA, or the acrylate-containing siloxane monomers offormula (I) may optionally be used in combination with any one of thevinyl ether-containing monomers disclosed in paragraph [023], especiallyin combination with BVE, DEGVE and/or EGVE.

Advantageously, the acrylate-containing siloxane monomers disclosed inparagraphs [026]-[031] above are present in the polymerizablecompositions of the invention in combination with any of the hydrophilicvinyl amide-containing monomers disclosed in paragraph [022]. Forexample, TRIS, SiGMA, SiGEMA, or the mono-functional acrylate-containingsiloxane monomers of formula (I) may optionally be used in combinationwith any one of the hydrophilic vinyl-amide containing monomersdisclosed in paragraph [022], especially in combination with VMA and/orNVP.

Similarly, the vinyl ether-containing monomers disclosed in paragraph[023], are, advantageously, present in the polymerizable compositions ofthe invention in combination with any of the hydrophilic vinylamide-containing monomers disclosed in paragraph [022]. For example,BVE, DEGVE and/or EGVE may optionally be used in combination with any ofthe hydrophilic vinyl amide-containing monomers disclosed in paragraph[022], especially in combination with VMA and/or NVP.

Furthermore, the acrylate-containing siloxane monomers disclosed inparagraphs [028] and [029] above are, advantageously, present in thepolymerizable compositions of the invention in combination with any ofthe vinyl ether-containing monomers disclosed in paragraph [023], andany of the hydrophilic vinyl amide-containing monomers disclosed inparagraph [022]. Thus, the polymerizable compositions of the inventionmay optionally include a combination of one or more of TRIS, SiGMA,SiGEMA, or the mono-functional acrylate-containing siloxane monomers offormula (I), together with both (i) a vinyl ether-containing monomer(such as BVE, DEGVE or EGVE) and (ii) a hydrophilic vinylamide-containing monomer (such as VMA or NVP).

As demonstrated by the specific examples, it has been found thatcombinations of the preferred acrylate-containing siloxane monomers,vinyl ether-containing monomers, and/or hydrophilic vinylamide-containing monomers of the invention provide contact lenses of theinvention with advantageous properties.

EXAMPLES

The following Examples illustrate certain aspects and advantages of thepresent invention, which should be understood not to be limited thereby.Example 1 describes contact lens processing methods, and Examples 2-9show exemplary polymerizable compositions that were used to make contactlenses using the methods described in Example 1. The resulting lenseswere optically clear, meaning that light transmittance between 381 nm to780 nm was at least 97% (measured in accordance with ISO 18369) and hadophthalmically-acceptable surface wettability. Additional physicalproperties of the lenses are provided in the examples below. Table 1shows the abbreviation used for each ingredient as well as its molecularweight, which was used to calculate the molar ratios shown in eachexample. The molar ratios provided for each formulation were determinedby dividing the unit amount of an ingredient by its molecular weight toobtain the relative molar amount of the ingredient in the polymerizablecomposition, and comparing that value to the molar amount of anotheringredient in the composition. For each polymerizable composition, therelative unit parts, based on weight, are shown. Molar percentages (mol.%) and weight percentages (wt. %) for each reactive ingredient areprovided, except that mol. % values of less than 0.01 are not provided.The mol. % and wt. % of a given component are relative to the totalmoles and weight, respectively, of all reactive components in thecomposition prior to initiation of curing.

TABLE 1 Molecular Abbreviation Compound Wt Si-1 Formula I above whereinR¹ is a butyl group, R² is 583 hydrogen, R³ is a methyl group, m = 4,and n = 1 Si-2 A compound of formula II above wherein R¹ and R² are9,300 methyl groups, m is 0, n represents an integer from X to Y, arepresents an integer of X to Y, and b represent an integer of X to YSi-3 Methacryloxypropyl terminated polydimethylsiloxane 4,500 AE2-Allyloxy ethanol 102 BVE 4-butanediol vinyl ether 116 DEGVE diethyleneglycol vinyl ether 132 EGDMA ethylene glycol dimethacrylate 198 EGMAethylene glycol methyl ether methacrylate 144 EGVE ethylene glycol vinylether 88 MMA methyl methacrylate 100 UV22-(3-(2H-benzotriazol-2-YL)-4-hydroxy-phenyl) ethyl 323 methacrylate(CAS no. 96478-0-0) pTPP Diphenyl (P-vinylphenyl)phosphine (CAS no.40538-11-2) 288 RBT1 2-Propenoicacid,2-methyl-,1,1′-[(9,10-dihydro-9,10-dioxo-1,4-anthracenediyl)bis(imino-2,1-ethanediyl)]ester (CAS no.121888-69-5) TEGDMA triethylene glycol dimethacrylate 286 TEGDVEtriethyleneglycol divinyl ether 202 V-64 2,2′-Azobis-2-methylpropanenitrile VMA N-vinyl-N-methylacetamide 99

Example 1 Silicone Hydrogel Contact Lens Fabrication

The chemical compounds listed in the tables in Examples 2-9 were weighedand mixed together to form polymerizable compositions. Eachpolymerizable composition was filtered using a 0.2-5.0 micron filter andstored for up to about 2 weeks at 2-10° C. prior to cast molding andcuring.

The polymerizable composition was cast molded by placing a volume of thecomposition on a female mold member and fitting a male mold memberthereon to form a contact lens mold assembly. The female and male moldmembers were made from a non-polar resin (e.g. polypropylene). Thepolymerizable composition was thermally cured to form a polymeric lensbody by placing the mold assembly in a nitrogen oven at the followingcycle: 30 min. N₂ purging at room temperature, 40 min. at 55° or 65° C.,40 min. at 80° C., and 40 min. at 100° C.

After curing, the male and female mold members were dry demolded and thepolymeric lens bodies were dry delensed from the male mold members. Thedelensed polymeric lens bodies were transferred to individual wells of awashing tray containing DI water and Tween 80 (washing solution). Afterseveral minutes, the washing solution was aspirated, and the wellsrefilled with washing solution; this step was repeated 1-2 times. Theextracted and hydrated lenses were placed into blister packagescontaining a buffered packaging solution, and the packages were sealedand autoclaved.

Example 2 Formulation 1

The polymerizable composition designated Formulation 1 shown in Table 2was used to make contact lenses using the methods described inExample 1. The composition had the following approximate molar ratios: a17:1 molar ratio of vinyl amide-containing monomer to vinylether-containing monomer; and a 61:1 molar ratio of monofunctionalacrylate-containing siloxane monomer to bifunctional acrylate-containingsiloxane monomer.

TABLE 2 Abbreviation Unit Amount Mol. % Wt. % Si-1 32 7.9 30.9 Si-3 40.13 3.9 VMA 45 64.0 43.5 MMA 13 18.6 12.6 EGMA 3 3.0 2.9 BVE 3 3.7 2.9TEGDMA 1 0.50 0.97 TEGDVE 0.2 0.14 0.19 pTPP 0.5 0.25 0.48 V-64 0.5 0.430.48 RBT1 0.01 0.01 UV2 1.3 0.40 1.3

Silicone hydrogel contact lenses made from this formulation had an EWCof about 57%, a modulus of about 0.70 MPa, an energy loss of about 40%,and a captive bubble dynamic advancing contact angle of from about 50 toabout 60 degrees.

Example 3 Formulation 2

The polymerizable composition designated Formulation 2 shown in Table 3was used to make contact lenses using the methods described inExample 1. The composition had the following approximate molar ratios: a7:1 molar ratio of hydrophilic vinyl amide-containing monomer to vinylether-containing monomer; and a 40:1 molar ratio of monofunctionalacrylate-containing siloxane monomer to bifunctional acrylate-containingsiloxane monomer.

TABLE 3 Abbreviation Unit Amount Mol. % Wt. % Si-1 26 6.6 25.1 Si-2 100.16 9.6 VMA 40 59.5 38.6 MMA 12 17.7 11.6 EGMA 5 5.1 4.8 BVE 7 8.9 6.8TEGDMA 1.2 0.62 1.2 TEGDVE 0.2 0.15 0.19 pTPP 0.5 0.28 0.48 Vazo64 0.50.45 0.48 RB 247 0.01 0.01 UV2 1.3 0.59 1.3

Silicone hydrogel contact lenses made from this formulation had an EWCof about 56%, a modulus of about 0.50 MPa, and a captive bubble dynamicadvancing contact angle of about 47 to about 51 degrees.

Example 4 Formulation 3

The polymerizable composition designated Formulation 3 shown in Table 4was used to make contact lenses using the methods described inExample 1. The composition had the following approximate molar ratios: a16:1 molar ratio of hydrophilic vinyl amide-containing monomer to vinylether-containing monomer; and a 41:1 molar ratio of monofunctionalacrylate-containing siloxane monomer to bifunctional acrylate-containingsiloxane monomer.

TABLE 4 Abbreviation Unit Amount Mol. % Wt. % Si-1 26 7.0 26.3 Si-2 100.17 10.1 VMA 40 62.9 40.4 MMA 12 18.7 12.1 EGMA 5 5.4 5.1 BVE 3 4.0 3.0EGDMA 0.5 0.39 0.51 TEGDVE 0.1 0.08 0.10 pTPP 0.5 0.27 0.51 V-64 0.50.47 1.3 UV2 1.3 0.63 0.01 RBT1 0.01 0.51

Silicone hydrogel contact lenses made from this formulation had an EWCof about 55%, a modulus of about 0.60 MPa, and a captive bubble dynamicadvancing contact angle of from about 47 to about 55 degrees.

Example 5 Formulation 4

The polymerizable composition designated Formulation 4 shown in Table 5was used to make contact lenses using the methods described inExample 1. The composition had the following approximate molar ratios:an 8:1 molar ratio of hydrophilic vinyl amide-containing monomer tovinyl ether-containing monomer; and a 56:1 molar ratio of monofunctionalacrylate-containing siloxane monomer to bifunctional acrylate-containingsiloxane monomer.

TABLE 5 Abbreviation Unit Amount Mol. % Wt. % Si-1 29 7.1 28.3 Si-2 80.12 7.8 VMA 44 63.3 42.9 MMA 14 19.9 13.7 EGVE 5 8.1 4.9 EGDMA 0.6 0.430.59 TEGDVE 0.15 0.11 0.15 V-64 0.5 0.43 0.49 UV2 1.3 0.57 1.3 RBT1 0.010.01

Silicone hydrogel contact lenses made from this formulation had an EWCof about 56%, and a modulus of about 0.65 MPa.

Example 6 Formulation 5

The polymerizable composition designated Formulation 5 shown in Table 6was used to make contact lenses using the methods described inExample 1. The composition had the following approximate molar ratios:an 8:1 molar ratio of hydrophilic vinyl amide-containing monomer tovinyl ether-containing monomer; and a 58:1 molar ratio of monofunctionalacrylate-containing siloxane monomer to bifunctional acrylate-containingsiloxane monomer.

TABLE 6 Abbreviation Unit Amount Mol. % Wt. % Si-1 29 7.5 27.9 Si-2 80.13 7.7 VMA 42 63.6 40.5 MMA 8 12.0 7.7 EGMA 6 6.3 5.8 DEGVE 7 8.0 6.7EGDMA 0.6 0.45 0.58 TEGDVE 0.1 0.07 0.10 pTPP 0.5 0.26 0.48 AE 0.4 0.590.39 V-64 0.5 0.46 0.48 UV2 1.7 0.79 1.6 RBT1 0.01 0.01

Silicone hydrogel contact lenses made from this formulation had an EWCof from 57% to 58%, a modulus of about 0.7 MPa, a tensile strength ofabout 1.5 MPa, a captive bubble dynamic advancing contact angle of fromabout 44 to about 48 degrees, a wet extractable component of about 5.1%,an ionoflux of about 2.9×10⁻³ mm²/min, and an energy loss from about 32%to about 33%.

Example 7 Formula 6

The polymerizable composition designated Formulation 6 shown in Table 7was used to make contact lenses using the methods described inExample 1. The composition had the following approximate molar ratios: a5:1 molar ratio of hydrophilic vinyl amide-containing monomer to vinylether-containing monomer; and a 68:1 molar ratio of monofunctionalacrylate-containing siloxane monomer to bifunctional acrylate-containingsiloxane monomer.

TABLE 7 Abbreviation Unit Amount Mol. % Wt. % Si-1 30 6.9 26.7 Si-2 70.10 6.2 VMA 44 59.9 39.1 MMA 8 10.8 7.1 EGMA 6 5.6 5.3 DEGVE 10 10.28.9 BVE 4 4.6 3.6 EGDMA 0.6 0.41 0.53 TEGDVE 0.1 0.05 0.09 pTPP 0.5 0.260.44 V-64 0.5 0.41 0.44 RBT1 0.01 0.01 UV2 1.8 0.75 1.6

Silicone hydrogel contact lenses made from this formulation hadacceptable dimensional stability, an EWC of about 61%, a modulus ofabout 0.5 MPa, a tensile strength of about 1.2 MPa, a captive bubbledynamic advancing contact angle of from about 45 to about 47 degrees, awet extractable component of about 4.55%, an ionoflux of about 3.8×10⁻³mm²/min, and an energy loss of from about 30% to about 33%.

Example 8 Formulation 7

The polymerizable composition designated Formulation 7 shown in Table 8was used to make contact lenses using the methods described inExample 1. The composition had the following approximate molar ratios: a7:1 molar ratio of hydrophilic vinyl amide-containing monomer to vinylether-containing monomer; and a 68:1 molar ratio of monofunctionalacrylate-containing siloxane monomer to bifunctional acrylate-containingsiloxane monomer.

TABLE 8 Abbreviation Unit Amount Mol. % Wt. % Si-1 30 7.07 27.4 Si-2 70.10 6.4 VMA 45 62.5 41.1 MMA 12 16.5 11.0 EGMA 6 5.7 5.5 BVE 5 5.9 4.6TEGDMA 1.4 0.67 1.3 TEGDVE 0.2 0.14 0.18 pTPP 0.5 0.24 0.46 V-64 0.50.42 0.46 RBT1 0.01 0.01 UV2 1.8 0.76 1.7

Silicone hydrogel contact lenses made from this formulation hadacceptable dimensional stability, an EWC of from about 55% to about 57%,a modulus of about 0.7 MPa, a tensile strength of about 1.3 MPa, acaptive bubble dynamic advancing contact angle of from about 47 to about53 degrees, a wet extractable component of about 4.1%, an ionoflux ofabout 3.6×10⁻³ mm²/min, and an energy loss of from about 34% to about35%.

Example 9 Formulation 8

The polymerizable composition designated Formulation 8 shown in Table 9was used to make contact lenses using the methods described inExample 1. The composition had the following approximate molar ratios: a7:1 molar ratio of hydrophilic vinyl amide-containing monomer to vinylether-containing monomer; and a 41:1 molar ratio of monofunctionalacrylate-containing siloxane monomer to bifunctional acrylate-containingsiloxane monomer.

TABLE 9 Abbreviation Unit Amount Mol. % Wt. % Si-1 25.2 7.04 25.2 Si-29.7 0.17 9.7 VMA 38.8 63.9 38.8 BVE 6.8 9.6 6.8 EGMA 4.8 5.4 4.8 EOEMA11.6 12.0 11.6 TEGDMA 1.2 0.68 1.2 TEGDVE 0.1 0.08 0.10 V-64 0.5 0.500.50 UV2 0.9 0.45 0.90 RBT1 0.01 0.01 pTPP 0.5 0.28 0.50

Silicone hydrogel contact lenses made from this formulation had an EWCof about 56%, a modulus of about 0.57 MPa, a tensile strength of about1.90 MPa, a wet extractable component of about 4.74%, and an energy lossof about 34 to 36%.

Example 10 Formulation 9

A polymerizable lens composition, designated Formulation 9 shown inTable 10 below was prepared by mixing the ingredients listed, where FMMis an acrylate-containing siloxane monomer having a molecular weight ofabout 1,500 and represented by formula (III) above; M5A is asilicone-containing component the same as, or similar in structure to,hydrophilic polysiloxane macromonomer A described in Example 2 of U.S.Patent Application Publication No. 2009/0234089 (Asahi Kasei Aime Co.,Ltd., Kanagawa, Japan); and EHMA is 2-ethylhexyl methacrylate.

The lens formulation was formed into lenses in the following generalmanner. Contact lens molds were injection molded from non-polarpolypropylene resin using conventional injection molding techniques andequipment. Each contact lens mold included a female mold member thatincludes a concave optical quality surface for forming the front surfaceof the contact lens, and a male mold member that includes a convexoptical quality surface for forming the back surface of the contactlens. The female mold member can be understood to be a front surfacemold, and the male mold member can be understood to be a back surfacemold.

An amount (about 60 μl) of the polymerizable lens composition was placedon the concave surface of the female mold member. The male mold memberwas placed in contact with the female mold member such that thepolymerizable lens composition was located in a contact lens shapedcavity formed between the concave surface of the female mold member andthe convex surface of the male mold member. The male mold member washeld in position by an interference fit between a peripheral region ofthe female and male mold members.

The contact lens mold containing the polymerizable lens composition wasthen placed in an oven where the polymerizable lens composition wascured at a temperature of about 100° C. for about 30 minutes. Aftercuring, the contact lens mold contained a polymerized contact lensproduct within the contact lens shaped cavity.

The contact lens mold was removed from the oven and allowed to cool toroom temperature (about 20° C.). The contact lens mold was mechanicallydemolded to separate the male and female mold members from each other.The polymerized contact lens product remained attached to the male moldmember. The polymerized contact lens product was then mechanicallydelensed from the male mold member to separate the contact lens productfrom the male mold member. The separated contact lens product was thenwashed in water, hydrated in PBS.

TABLE 10 Abbreviation Unit Amount FMM 30 M5A 15 VMA 45 MMA 12 EHMA 2 BVE6 TEGDMA 0.15 TEGDVE 0.1 V-64 0.5

In one example, the polymerizable composition of the invention does notcomprise a siloxane monomer represented by formula (III) above, where nis an integer from about 10 to 15. In another example, the polymerizablecomposition of the invention does not comprise EHMA. In yet a anotherexample, the polymerziable composition of the invention does not includeFormulation 9.

Although the disclosure herein refers to certain illustrated examples,it is to be understood that these examples are presented by way ofexample and not by way of limitation. The intent of the foregoingdetailed description, although discussing exemplary examples, is to beconstrued to cover all modifications, alternatives, and equivalents ofthe examples as may fall within the spirit and scope of the invention asdefined by the additional disclosure.

A number of publications and patents have been cited hereinabove. Eachof the cited publications and patents are hereby incorporated byreference in their entireties.

What is claimed is:
 1. A silicone hydrogel contact lens comprising: apolymeric lens body that is a reaction product of a polymerizablecomposition comprising a) at least one hydrophilic vinylamide-containing monomer; b) at least one acrylate-containing siloxanemonomer; and c) at least one vinyl ether-containing monomer, with theproviso that the at least one acrylate-containing siloxane monomer doesnot comprise a siloxane monomer represented by formula (III),

where n is an integer from about 10 to
 15. 2. The contact lens of claim1, wherein the polymerizable composition has a total amount ofhydrophilic vinyl amide-containing monomer of from about 50 mol. % toabout 80 mol. %.
 3. The contact lens of claim 1, wherein thepolymerizable composition has a total amount of acrylate-containingsiloxane monomer of from about 2 mol. % to about 15 mol. %.
 4. Thecontact lens of claim 2, wherein the polymerizable composition has atotal amount of vinyl ether-containing monomer of from about 2 mol. % toabout 20 mol. %.
 5. The contact lens of claim 1, wherein thepolymerizable composition has a molar ratio of total amount ofhydrophilic vinyl amide-containing monomer to total amount of vinylether-containing monomer of from 2:1 to 30:1, respectively.
 6. Thecontact lens of claim 1, wherein the polymerizable composition has amolar ratio of total amount of hydrophilic vinyl amide-containingmonomer to total amount of vinyl ether-containing monomer of from 4:1 to20:1, respectively.
 7. The contact lens of claim 1, wherein the at leastone hydrophilic vinyl amide-containing monomer is selected fromN-vinyl-N-methyl acetamide (VMA), or N-vinyl pyrrolidone (NVP), or acombination thereof.
 8. The contact lens of claim 1, wherein the atleast one hydrophilic vinyl amide-containing monomer consists ofN-vinyl-N-methyl acetamide (VMA).
 9. The contact lens of claim 1,wherein the at least one vinyl ether-containing monomer is selected from1,4-butanediol vinyl ether (BVE), or ethylene glycol vinyl ether (EGVE),or diethylene glycol vinyl ether (DEGVE), or 1,4-cyclohexanedimethanolvinyl ether (CHDMVE), or a poly(ethylene glycol) vinyl ether having from4 to 10 ethylene glycol units, or a poly(ethylene glycol) vinyl etherhaving more than 10 ethylene glycol units, or any combination thereof.10. The contact lens of claim 1, wherein the polymerizable compositionfurther comprises at least one vinyl-containing cross-linking agent. 11.The contact lens of claim 10, wherein the polymerizable composition hasa total amount vinyl-containing cross-linking agent of from about 0.02mol. % to about 0.20 mol. %.
 12. The contact lens of claim 10, whereinthe at least one vinyl-containing cross-linking agent is selected fromdivinyl ether, or divinyl sulfone, or triallyl phthalate, or triallylisocyanurate, or diallyl phthalate, or diethyleneglycol divinyl ether,or triethyleneglycol divinyl ether, or any combination thereof.
 13. Thecontact lens of claim 10, wherein the at least one vinyl-containingcross-linking agent comprises a divinyl ether.
 14. The contact lens ofclaim 1, wherein the polymerizable composition further comprises atleast one acrylate-containing monomer.
 15. The contact lens of claim 1,wherein the polymerizable composition is substantially free ofhydrophilic polymer.
 16. The contact lens of claim 1 that is free ofpost-polymerization surface modification.
 17. The contact lens of claim1 sterilized in a sealed package.
 18. A method of manufacturing thesilicone hydrogel contact lens of claim 1 comprising: polymerizing thepolymerizable composition to make the polymeric lens body, and washingthe polymeric lens body with a washing liquid to remove unreacted orpartially reacted components from the polymeric lens body.